Radiographic images are important in the field of dental implants for treating partially edentulous mouths. Dental implants are a means for restoring missing teeth and represent an alternative to removable dentures and fixed partial dentures to significantly improve a patient's dental health and quality of life. In the treatment plan, it is necessary for the practitioner to accurately determine whether sufficient space exists between two teeth and their roots in order to successfully implant a tooth in that edentulous space. Commonly, a successful anterior dental implant requires a minimum width between adjacent teeth of 6 mm (with a narrow margin of error) at the cemento-enamel junction. Additionally, the practitioner also needs to determine whether the patient has enough jawbone to support a dental implant. At least 10 mm of jawbone height is necessary. Radiographic images of the patient's mouth provide this information.
However, a problem with existing radiographic images is distortion in the images which limits the practitioner's ability to accurately determine the required measurements. Currently, periapical x-rays are typically taken with an XCP paralleling device by the Rinn Corporation. The XCP device allows a paralleling of the x-ray beam to the longitudinal axis of the bite block/film holder such that the x-ray beam will irradiate the film in a perpendicular manner. However, while the XCP allows a focusing of the x-ray beam onto the x-ray film, it does not provide any control over distortion of the radiographic image due to operator error and anatomical variances.
Distortion can take the form of either foreshortening or elongation due to palatal depth variations in different patients. A shallow palate would be most likely to cause a foreshortening of the root in the radiograph image due to the angle of the bite block in the patient's mouth once the patient bites down on the bite block. Similarly, a deep palatal vault may cause an elongation of the root in the radiograph image again due to the angle of the bite block in the patient's mouth. Another type of distortion frequently found in radiographic images is the mesio-distal distortion. The mesio-distal dimension becomes distorted due to any rotation of the bite block in the patient's mouth. If the x-ray cone is not pointed normal or perpendicular to the front surface of the teeth, then the adjacent tooth will cast a shadow on the radiographic image because it will be either closer to the cone or farther away from the cone than the tooth or spacing to be radiographed, depending on the angle of the cone. The resulting image causes the adjacent tooth to appear closer or farther away than the true spacing depending on the angle of the cone with respect to the tooth. Any distortion in the radiograph adversely affects the practitioner determination of actual jawbone height and edentulous spacing, thus introducing inaccuracy into the treatment process and hence increases risk to the patient.
Hence, a need exists for a method in which a dental practitioner can obtain radiographic images of a patient's teeth with minimal distortion and with a means to measure any remaining distortion in the images.